;;; any other solutions?
;;;
(defun p20 ()
  (defun p20-inner (k result)
	(if (= k 0)
	    result
		(p20-inner (truncate (/ k 10)) (+ result (mod k 10)))))
 (p20-inner (fabtorial 100) 0))

(defun fabtorial (n)
  (if (< n 2) n
	  (* n (fabtorial (1- n)))))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(format t "~a~%" (fabtorial 3))
(format t "~a~%" (p20))
